Password Size Limits and RSA Key Sizes

The maximum length of the password that can be encrypted depends on the chosen RSA key size (modulus) and padding type, as follows:

Key Bits	Cipher Size	Padding Type	Pad Bytes	Maximum Password Length
512	64 bytes	PKCS#1 v1.5	11	53 characters
512	64 bytes	OAEP with SHA-1	42	22 characters
512	64 bytes	OAEP with SHA-224	58	6 characters
512	64 bytes	OAEP with SHA-256	66	Not possible
512	64 bytes	OAEP with SHA-384	98	Not possible
512	64 bytes	OAEP with SHA-512	130	Not possible
1024	128 bytes	PKCS#1 v1.5	11	117 characters
1024	128 bytes	OAEP with SHA-1	42	86 characters
1024	128 bytes	OAEP with SHA-224	58	70 characters
1024	128 bytes	OAEP with SHA-256	66	62 characters
1024	128 bytes	OAEP with SHA-384	98	30 characters
1024	128 bytes	OAEP with SHA-512	130	Not possible
2048	256 bytes	PKCS#1 v1.5	11	245 characters
2048	256 bytes	OAEP with SHA-1	42	214 characters
2048	256 bytes	OAEP with SHA-224	58	198 characters
2048	256 bytes	OAEP with SHA-256	66	190 characters
2048	256 bytes	OAEP with SHA-384	98	158 characters
2048	256 bytes	OAEP with SHA-512	130	126 characters